Lithium-based batteries are ubiquitous in modern-day energy supply systems. However, the volatile nature and the flammability of the battery electrolytes remain critical safety issues. Polymer electrolytes have been proposed to be an alternate, safe option. Here we show an amphiphilic polymeric electrolyte design based on a siloxane polymer backbone and ionic liquid side chains, which can achieve a high salt solubility (molar ratio Li: monomer = 8:1). The high lithium salt concentration liquified the polymer-salt mixture. This liquid-state polymeric electrolyte has a room temperature ionic conductivity of 1.6 mS/cm and a viscosity of 0.08 Pa×S. When paired with commercially available NMC cathodes, it can operate at 25 ˚C with C/10 rate (~140 mAh/g) and at 100 ˚C with 2C rate (~180 mAh/g). As a solvent-free silicone-polymer based liquid electrolyte, it is non-volatile and non-flammable. Our work extends the ionic conductivity range of polymer-based electrolytes and highlights their potential as next-generation safe battery electrolytes.